The reaction of gaseous N 2 O 5 with solid NaCl at 298 K: Estimated lower limit to the reaction probability and its potential role in tropospheric and stratospheric chemistry

• Published in: Geophysical research letters Vol. 18; no. 1; pp. 17 - 20
• Main Authors: Livingston, F. E., Finlayson‐Pitts, B. J.
• Format: Journal Article
• Language: English
• Published: 01.01.1991
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/90GL02595

Gaseous N 2 O 5 /air mixtures were flowed over solid NaCl at 298 K and the gaseous product ClNO 2 measured using FTIR. With excess NaCl, one ClNO 2 was produced per N 2 O 5 in the initial mixture, and from the contact time between N 2 O 5 and the salt, a lower limit to the fraction of collisions leading to reaction was estimated to be 2.5 × 10 −3 . This reaction is sufficiently rapid that it may lead to the formation of ppb levels of ClNO 2 overnight in polluted marine urban areas. The ClNO 2 will photolyze at dawn to give chlorine atoms which initiate the photooxidation of organics in a manner analogous to OH. This reaction may also play a role in remote Arctic chemistry if the reaction is significantly faster than our lower limit. This supports the hypothesis of Michelangeli et al. (1990) that the N 2 O 5(g) + NaCl (s) reaction may contribute significantly to stratospheric chemistry after the eruption of alkalic volcanoes such as El Chichon.